1st Video - FPS
. Gun sounds don't match the environment - I hear gun handling sounds at 48sec recorded in a room but being used outside - my immersion is removed. Better to record your sounds under the cover of a heavy duvet, or in a closet lined with pillows and blankets to get a more dry sound.
. Felt the gun sounds lacked guts, they're not bad, but could be a lot better - a little more bottom end and definition. The first one felt more like a starter pistol - guns need to sound satisfying to use.
. Monsters - yeah these things can be difficult to get right - concentrate more on the sound design of the monsters, layer snarls, wet mouth sounds together with growls to create these. Single sounds feel fake and don't provoke any sort of fear. Sound is your instrument to convey emotion. Part of the satisfaction of killing a monster is how scary it sounds and the death throes after its had its killing blow.
. Ambiance felt lacking of emotion it could have conveyed fear or anxiety more with more spot fx and tone.
2nd Video - Fantasy
. The music set the mood nicely, though it wasn't highly memorable, more attention to melody would be nice.
. It's hard to showcase sound design and music together if the music level is louder, in this example I felt like the music was the main focus. Try changing your mixing so the music supports the scene rather than dominates it.
. Sounds themselves were suitable but didn't shine in any particular way. I liked the sound design on the electricity shimmers at the beginning and the shimmer of the girl turning to dust at the end.
Hope this helps.