With Half-Life conversion. You can found that conversion in DOOM WAD STATION.
Do you want the HL2 weapons? Download here : http://www.filefront.com/15696455/hl2-weaponsBETA7.wad/
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https://www.youtube.com/watch?v=68FA_tC5u4Y
Until get whistle-blown by a legendary modder.
Meme based on a true story : https://www.youtube.com/watch?v=h5YrdarJ_7U&ab_channel=CarlosSanchez
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https://www.youtube.com/watch?v=NMR8dAjQMdw
This area is a big dome which the light is the UV, technically lights that can simulate sunlight, the purpose of this one is ecology, green technology which people can farm with the plants and feed animals. Also it's here where the rough route is begins, we meet more brutal enemies and then for the final floor it's the "super" ones.
I didn't mentionned in the previous parts that I've made achivement system but poorly way, also I didn't able to find easter egg items.
And oh, sorry early if you see some writing mistakes again and some cuts because I made some pause and I had to fix some issues, so don't be surprised. ._.
Moral of the story for this area : real sun light is best for you, not artificial because you don't know if there's secondary effects! No sun in several days, you'll look like shit! (for real, I've heard that in the old days in cambodia, for punish some thug, we isolate it in a cell which there's no sunlight, then 1 month, the guy can't stand the sun)
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https://www.youtube.com/watch?v=QFKA7YJpRm8