Ancient Museum’s main theme is about an ancient relic museum that also contains (mostly) ancient relics.  Also, the surrounding environment “supports” the museum like a pillar.
TNT can blow the c up into a potentially easier-to-control spot.  As far as I know, if you want the c to stay up there, you can only blow it up to the left, but that’s not a huge bias.   If you don’t want the c up there, then shoot it down.  
I added an “Apocalypse” version of this level for fun.  Only the music, a text string, the tile-set, and, of course, the level names are different from the other.   
This isn’t meant to take great advantage of jj2+‘s features.  So, “Ancient” Museum indeed.
The “weird lifeforms” are a type of fictional and aggressive mangrove trees.
I hope you have fun! (When will I ever stop making levels for this game?)
EDIT: So much for consistency, but a couple of warps at the left sides of the levels had the wrong ids, which is an important problem.  This is more of a fix than an “update” really.
       
            
        Levels: Me, of course.  Tilesets: Epic (Pyromanus for the conversions).  Music:  "Fifth" by Blue Ion and "All Hallows Eve" by Siren.  Thanks to all of my testers: Superjazz, Purplejazz, Snooze, Cooba, Ragnarok, Sir E, Mastersven and anyone else less notable.  
      
        
      
      
        
          
          
          
        
          
            AM.j2l | 
          Ancient Museum | 
          13.24 kB | 
        
          
            AMA.j2l | 
          Ancient Museum [Apocalypse] | 
          13.28 kB | 
        
          
            HauntedH1Hell.j2t | 
          Haunted House Hell | 
          296.91 kB | 
        
          
            HauntedH1Lite.j2t | 
          Haunted House Lite | 
          299.99 kB | 
        
          
            all hallows eve.s3m | 
          All Hallows Eve | 
          675.28 kB | 
        
          
            ion_fth.s3m | 
          Fifth | 
          897.72 kB | 
        
          
            AM.j2as | 
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          0.44 kB | 
        
          
            AMA.j2as | 
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          0.44 kB |