LODEBAR'S PROFILE

I made a game with all unique assets for a game jam in october. I'm developing on my main PC which runs Windows 7, and everything is working as intended in testing.

However, I had somebody do some playtesting on Windows 10, and every time any spell that uses the Buff or Debuff animation was cast, it would play such a sound from the RTP rather than the imported sound file that is inserted in the animation.
I have since tested on my old Windows XP laptop, and the same audio errors happened consistently.
(I don't necessarily think the problem is with the OS, but these are the different environments I've been able to test with.)

I've extracted the same archive to a separate folder on my Win7 PC, but I can't replicate the problem. As such I don't even know where to begin attempting a fix. Everything looks fine in the engine.

And I think it was just the Buff & Debuff animations. I think my custom Heal, Damage, and Magic Damage animations worked as intended all around. As do all other custom assets.

I would really appreciate any and all insight. If you'd like to help test, I'd be most grateful.

Here's the game disc, as made by the Steam version of RM2K3
And here's a save where each character has a buff/debuff
All you'd have to do is walk around, get into a random encounter, and cast Speed Up and Defend Down. If they play buff.wav and debuff.wav, great! If they play anything else like Down.wav, there's a problem and I wanna be able to fix it.

I'm still making a futile attempt at an oldschool game on an oldschool engine. As I've been testing what's done so far, adjusting stats and exp and money, I started noticing I'm getting a lot of critical hits. Like, ridiculous amounts. The last dungeon practically every attack every round every battle was a crit.

As far as I can tell, crit rates are governed by a number on the Hero tab in the database. At 100 every attack should crit, and at 1 you'd only have a 1% chance of critting. Right? Or is it the opposite? Because I've had my characters have a 5% chance, and I'm flooded with crits. Well, there's one exception. The guy whose feature is supposed to be critting a lot. His % was 25, then 33, now 45, and he just won't crit practically ever. Meanwhile I've lowered the others to 2% and they're getting more crits than ever.

Is there something I can do to work around this or do I have to live with an apparent kink in the engine?

I have only just now noticed how much faster games are in full screen. Battles load faster, the movement speed increases, and attack animations go by quicker.

The last part is a problem. I have one character whose attack is supposed to be in sync with a sound effect. In the windowed mode it's perfect, but in fullscreen the animation is over while the sfx is still playing.

Is the slowdown in windowed mode common for everyone, or is it just because I'm on a crummy old netbook? Should I optimize the animations for fullscreen play in the age of 21+ inch monitors?