Depends, if you're looking for an FPS game then its a top notch FPS. If you're looking for a traditional Halo game then its a disappointment
Campaign was tragically bad. Art and graphics wise it hit the nail on some parts other parts not so much.Structures and buildings have a very drastic difference in art style compared to the original trilogy, scenery, vegetation, land formations are great however. A lot of glaring shading and graphical effects are used to keep the game at 60 FPS. Gameplay wise H5 is a huge step down.Prometheans arent fun to fight, fighting the same boss 5+ times isn't something to go crazy over either and the A.I is pretty mediocre. Story wise the community consensus is that it's the worst in the series. Story never really goes anywhere, many scenes are very questionable, many scenarios make no sense, overall pretty terrible story.
Multiplayer wise the game can be bad or great depending on what you were expecting. Mechanics are very smooth and common abilities from other FPS games are introduced to keep movement smooth and user friendly. Game-play is very fast compared to predecessors and a lot more gun fight focus is put on reaction times and overall aim. Arena is overall balanced, some iconic gametypes missing from previous Halo's but overall a decent pool of game-modes and playlists. Warzone is very chaotic and has a lot ups and downs, mixed experiences. When it works properly its a blast to play, when it doesn't work out it can get very frustrating. Games are mainly decided on who pulls out better reqs, a few other factors can lead to victory but pulling out reqs is the easiest way to win. Reqs are pay to play and borderline pay to win, many are severely overpowered and give opposing players little opportunity to fight back. Vehicle play is mixed as well, depends on how lucky you are ie what reqs your enemies pull out. Arial vehicles severely overpowered, and most land vehicles are severely underpowered. Social playlist is also found in H5, random casual gametypes such as action sack, infection, BTB and a few unranked slayer and objective gamemodes can be found in the social playlists.
Forge is the best in the series, controls are VERY confusing at first but after some time become very simple. U.I is not very user friendly but controls work perfectly once mastered. Thousands of objects to place, map options never before seen in other iterations of forge, and many quality of life changes can be found in H5's forge. A few sandboxes to play with as well.
if you want a rating: As an FPS this game is a must buy at the moment(8\10). If you're looking for the iconic Halo experience then cautionary measurements are recommended(4\10). Watch videos and do more research on H5 before buying it. However it is only a few 20$ at the moment so it's up the consumer at that point. I believe its worth the 20 at least.