Looks adorable :) but what could this retro game possibly be doing that would require a 3.4GHz i5??? o_O
Welcome to the perils of having an idea and not really thinking it through. When making Rex, we wanted the entire game to be one big open level, with no loading. As a result, the game is one big open level that's active and loaded all the time, which uses a lot more CPU than you'd think. We've tried to optimize it so that things not immediately visible on screen don't use up as much memory or processing, but there are limits to what we can do with Construct2.
The game can run on lower specs, especially if you toggle Performance Mode which removes a lot of particle systems, but we're not sure where the minimum is since we've only got our own PCs to test with. The recommended specs are based on our own systems, which is probably a bit overkill, but we'd rather be safe than sorry.
We've learned a lot from making Rex, and if we were going to try doing an open world platformer again, we'd certainly do it differently.