Oh sweet! The difference in browser performances is a common issue most of the games I publish have, I'm glad to hear this one was at least playable in Firefox!
And I agree, Yasameen feels a bit too weak. Her attack speed is quicker and accuracy is higher, however, the firerate is lower than other characters and definitely the least damage. I added her in the game last, so I didn't do enough testing with Yasameen. Thanks a lot for the feedback though! I just adjusted Yasameen's stats, if you could try her again and lemme know what you think I'd appreciate it!