I dig it! I especially appreciate that the character portraits appear to be in...traditional physical media?! Which is glorious, and deeply appropriate for something that's an homage to Twisted Metal (and maybe a little Carmaggedon?) It would feel deeply wrong if those portraits were super polished modern digital art.
Gameplay's simple but fun. Basics seem solid, though even with the tweaks I think the AI may be spending more time focusing on the player when it should have more of a chance of infighting. Not terrible though. Could use a little more (or any) skid, though I have no idea how hard this would be to program.
UI could also use a little more polish: Not an insane amount, but I think it's pretty good already: just a LITTLE more would help it feel a lot more "complete", help things flow a little better etc. An actual exit button on the character info for example would help a lot (I was able to figure out esc without too much trouble, but the typical user won't).
Not a bad start at all though. You say you don't want to charge, and fair enough, but if you did end up polishing up the UI and overlay, fancying up the effects a little etc, I can absolutely see this being worth five or ten bucks. If you ever go crazy and decide to dump some money into this, I'd absolutely nominate some VAs for taunts being the way to go though. It's rough having a Twisted Metal tribute with no taunts.