Update 0.98.5 'Let there be light'

1. 'Seaport' level improvements:
- HOTFIX: resolved 'darkness' issue (hope this time it's final :) );
- added a few checkpoints;
- tweaked some enemies' & pickup locations;
- adjusted damage zones;

2. 'Epilogues Repository' level improvements:
- added a few checkpoints;
- tweaked some enemies' & pickup locations;
- improved lighting;