Meticulously detailed virtual toy cars fuel racer Hot Wheels Unleashed

Brian Crecente
Michele Caletti started working at Milestone in 2003 as an audio programmer, then stepped up to Lead Programmer with the reboot of the Superbike franchise, and later became Game Director. He worked on most of the MotoGP games, and contributed to creating the Ride franchise. Since 2020, he has been the Executive Producer, overseeing all game production teams, and working on future IPs and franchise development.
Digging into more than 50-years worth of die-cast hot rods, muscle cars, ice cream trucks, and much more, developer Milestone is creating a racing game that doesn’t just let you control your favorite Hot Wheels, but also live the fantasy of playing with the toys in a world slightly unhinged from reality.

Hot Wheels Unleashed promises to tap into the 1:64-scale world of both Mattel’s popular line of more than 800 toy cars and those colorful orange tracks, delivering a chance to build endlessly looping, spider-haunted raceways and then race them with friends.

We chatted with Hot Wheels Unleashed executive producer Michele Caletti about how the studio is translating the popular toy into a digital experience, finding the sweet spot between over-the-top toy play and balanced racing, and how Unreal Engine helped the developers breathe life into their concepts.

Milestone has been making authentic racing games for more than 25 years; what was it like to transition over to an arcade racer based on toy cars? Were there any particular challenges you ran into?

Gameplay is a key factor so we had to develop a new physics system for the title. We didn't want a scripted feeling, so it's all actually physics-based. This added to the challenge—keeping the cars on the track, making handling fun, but managing jumps and ramps. But the effort paid off, I think. Also, the track editor is very complex, being the same the designer used to create the built-in tracks; it's very powerful because it allows you to twist and bend road pieces. We expect some amazing creations from players.

There is a wide variety of approaches to racing games, even arcade racers. How would you describe the approach you took to Hot Wheels Unleashed?

As I was saying, most kart-like games don't have actual physics. The cars behave on scripts, so there is little feeling of weight and reactions are always the same. In Hot Wheels Unleashed, instead, the core gameplay—driving the cars—feels substantial and rewarding. Also, we focused on some mechanics like boosting and didn't want weapons that would overcomplicate the game. It had to be fun to play even alone, so that races feel always on the verge of chaos, yet in control.

Were there any particular video games, television shows, or movies that you drew inspiration from when coming up with your approach to the game? 

We took inspiration from the Hot Wheels clips that Mattel makes; you can find them on YouTube. So, real cars obviously, real sets, and we made the cars like the real toys. It all feels very real, unlike all the other video games from the franchise. These are the real Hot Wheels cars, down to the details, and you can play with them like never before.
Image courtesy of Milestone
What made Unreal Engine a good fit for Hot Wheels Unleashed?

Unreal Engine is very powerful for visuals, so we could achieve top-level graphics, and this is very important for players, but also enabled us to recreate the realistic look we wanted. It's quite evident on next-gen consoles that display these amazing visuals at 60 FPS. It's also very powerful for creating physics. We have extensive experience in this. We could control all the aspects and tune the gameplay the way we wanted. Finally, Unreal Engine enabled us to optimize the game code and assets to achieve dense and realistic environments with a solid framerate, which is a very important aspect for such a frantic game.

A big part of Hot Wheels is the fantasy of ownership and racing. How did you balance that inner vision of how these cars look and behave with the reality of the die-cast models in the game?

Cars are represented as they are. You can read the model on the bottom of the cars, you can see the little details represented 1:1. We laser-scanned most of the cars so we can hit a soft spot in collector's hearts. And the City Rumble mode—the career mode—puts rewards, cars, and challenges in equal proportions so unlocking new cars is a pleasure. We searched for players' favorite cars and we're getting an amazing response from the fanbase.

Were there any ways in which Unreal Engine’s toolset helped breathe life and detail into the in-game models? 

One of the greatest challenges was lighting. We wanted to achieve realistic visuals, but at the same time it had to be playable. So we made tons of experiments with post-render effects, baking, and motion blur. We tried many setups and doing so in Unreal is a breeze. We have open-air environments, but also artificial lights, flashy neons, and Unreal lets us manage this all at best quality.

There are more than 800 models and 11,000 variations of Hot Wheels. How did you go about deciding which ones to include in the game and what will you be looking to do as you roll out new cars post-launch?

We made some extensive searches, and admittedly, many of us were long-time Hot Wheels fans (I have a collection of more than 100, for example). So we selected a mix of old and new, trying to make fans of all kinds happy. There are many ways to be a Hot Wheels collector. You might be focused on original cars or OEMs, so it wasn't easy. We've planned extensive post-launch support including many more models, extending the experience and keeping the game fresh for a long time.
How did you determine what attributes to give each vehicle in the game and how does that impact the gameplay?

There are several rarities in the game, from common to Super Treasure Hunt, and each class increases speed, handling, and boost. We wanted to have all the cars in each class be potential winners, but to have different flavors, so the hard part was to balance all the skills to keep the competition even. For some cars it was straightforward (a muscle car will have blistering acceleration, but not an incredible top speed). For some others, we had to use lots of imagination. That's one of the pleasures of making such a game.

Your track building looks extremely robust. How much did you stick to the reality of using and building with Hot Wheels’ tracks in the real world and how much are you letting players just do whatever they want with them in the game?

The track editor you can use in-game is the same used by designers to create all the tracks you see in it, so it had to be expressive and robust! We used mainly real track pieces, but for some special ones, we had to take inspiration and invent some game mechanics that could be challenging and fun. Given some time and experience, players can create tracks on par with ours, and possibly go further with crazy and challenging designs. We always tried to keep the tracks fun and not frustrating, but I’m sure players will soon pull out some really evil designs.

There’s a scene in one of the trailers where a Hot Wheels car falls off the track in a race, and suddenly you’re dropped out of the fantasy and see a tiny car drop onto the floor. Are there moments where you do the same sort of return to reality moments in gameplay?

Yes, you never get respawned automatically unless you miss a checkpoint. This is because there are many hidden shortcuts you can take, some obvious, some less so. So you can try to wander, to bounce around, and see if you can get back on track. The concept of shortcuts is integrated into the very foundation of the game. Again, we expect players to exploit this in a very good way in custom-made tracks.
The game features a spectacular soundscape. How did you decide what each vehicle would sound like in a race, especially those that aren’t based on real vehicles or existing IP?

For car sounds, our designers had a lot of fun in trying to match the visuals. For real or realistic cars, it can be easy, for the wildest model, it's more complicated, and so even more fun. We wanted to balance car sounds with environment sounds (special pieces make a lot of noise; for example, the spider spits and hisses) but also the dynamic music score, that reacts to the race situation from relatively calm to frantic status. The risk was to have some part dominant or to have audio mayhem but our sound designers managed to blend it all perfectly.

How are you using some of the next-gen features of the PlayStation 5 and Xbox Series consoles in those versions of the game?

Next-gen consoles allowed the game to have almost no loading time, and this is very refreshing. Also, we could achieve 60 FPS in all situations, with no compromise on visuals. PlayStation 5 has some very interesting joypad haptic feedback functions that help to convey even more to the player; it's the classic "more than the sum of its parts" situation, and it was very nice to be working on this.
Is there any particular gameplay or visual element of your game’s design you’d like to call out and explain how it was achieved?

All the special track pieces have a history on their own. The spider was one of the first developed and had infinite revisions. We had to fine-tune the spiderweb shots to make them random, but not too much, and precise, but not frustrating. Challenges don't have to feel cheap or bashing. We want players to feel on a knife's edge, and yet in control. There were dozens of try-play-change cycles that led to refinement, and we repeated this for all the pieces. And then imagine the track design. We were creating a gameplay system from scratch, but the result, I think, is amazing.

Unreal Engine 5 is now in Early Access. What excites the team most about the next generation of game development?

It opens up to a new generation of games, to completely new workflows for asset creation. There is a lot to learn, to experiment with, and it'll take time, but it looks like the perfect tool to unleash the power of this new hardware generation. And also, removing limitations and redefining what's possible will open up new roads for gameplay too, so it's more than visuals, and this is the most exciting aspect.
Thanks for taking the time to answer these questions. Where can people find out more about Milestone and Hot Wheels Unleashed?

For more information about Milestone visit and for more information about Hot Wheels Unleashed check out

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