Not gonna lie I love incremental games like Cookie clicker, and this is a great small game! Although there is nothing to do at endgame, so i stopped here: 
Also I think it was better to increase upgrade gain rather than base multi and speed, because with base upgrades once you have enough multi you can enter isekai++ on first roadkill, reset, rinse and repeat. It's a snowball from here until upgrades start costing 10+, then its back to normal loop. Also speed and acceleration are useless after couple of upgrades, since autoclicker does not speed up with them. I think it could be fixed with ITRTG's approach - reset resets all stats to 0 and you have to do at least something to gain them back. That could be the fact that gem upgrades don't touch base stats or the fact that usually at some point coin upgrades start falling off unless gem upgrades have needed level. (Funnily enough ITRTG does both) Sad that the theme wasn't Isekai(((