The main mythic system is excellent and highly recommended. It got me back into tabletop RPGs by eliminating prep. It is not perfect but well worth the money and very useful. In addition it teaches scene-framing techniques that are useful for all GMs and for anyone playing storygames or more narritive games that use this technique.

This supplimenis interesting but not essential. I think the key ideas are in the base Mythic GME.

This is a nice little product that describes a single dungeon complex of approx 15 locations with hooks for further campaign-style play. There is good information for the GM on the feel/atmosphere at each dungeon level and the monsters are flavorsome, if just new twists on old favorites. The dungeon is very linear so player choices are a bit limited, but this does make it suitable for play in 1-2 short sessions. As a burial complex the dungeon does make use of traps and the module includes good technical descriptions of them. However for lower level characters these encounters are going to be very deadly and I'd recommend that the GM needs to give some additional clues about their presence. The module includes new items, monsters and magic, which means that it can expand your game.

The use of perception-based skill checks struck me as odd in an OSR-style game. Especially as one of them must be made to gain entry into the dungeon in the first place. However enough description is provided that a DM can easily dispense with the checks if desired and instead rely on the players describing their character's actions when searching.