So, what can you actually expect from a PK3 that's over 150MB?

35 new maps all from scratch (+4 secret maps)
18 powerful weapons (some totally new ones)
20 different powerups to play with
30 additional new monsters (some totally new ones)
5 different gamemodes (e.g. Deadline, Core, ...)
1 complete new HUD (add. info on screen)
unique voice acting & announcers
full soundtrack with exclusive songs by Lexus Alyus
32bit skyboxes, fog, lights and environment
dynamic lights for actors and in maps
cinematic sequences for gamemodes and endings
special effects, atmospheric and beautifl
full multiplayer for Skulltag, up to 8 players
bounty, earn credits for killed demons
dynamic skill for all skill settings and player counts
hub system with several tiers to battle through
shop system with countless items to buy

...and many many more things for you to discover in this huge and complex project. Don't stop playing, there is even more you haven't seen!