Pros:
HMP is a very accessible, beginner-friendly course that's not afraid to mix in some longer holes.
It's got all the basics of amenities. Tee signs show everything. Concrete tees. DISCatchers. Some baskets have colored spokes for next tee indication. Plenty of benches in the multi-use park. The park atmosphere is totally unobjectionable, as HMP has a little bit of everything: baseball, walking trails, picnic spots, horseshoes, pavilions, and a couple of interesting exhibitions (one train car and one fighter jet).
In terms of the gameplay, HMP is a great example of a short, friendly course that still leaves challenges for the non-beginner. There are some short, technical holes (like the ~200' doglegs with woods on (10)-(11)), some longer, moderately wooded holes (I enjoyed (2) and (18)), open holes, and tunnels. Length ranges from about 150' on the treacherous (9) to about 450' through a tunnel on the course's par 4, hole (4). Considering the space he had to work with, Johnson did a very good job at introducing variety of terrain, rough, scenery, and shot choice. You'll battle it out with trees sometimes; other times you'll need to just avoid that OB on the side; and once or twice you can enjoy a solid 300' midrange drive.
Thinking back over my round, the hole-by-hole variety is impressive. I'll pick four random holes to illustrate: (3) lies straight ahead, but trees will force you to go with a FH hyzer/BH annie over a retention pond. (8) is no gimme at 375' with dense shrubbery and a ditch on the right and a hill and walking path on the left. (11) plays at just 195', but it's a dogleg right with the basket on top of a hill in a 30-foot tunnel. (18) closes with a 260' straight shot through a small gap or a big forehand hyzer around everything.
This is also a great park for beginner or recreational players. The rough is mostly not too bad (except in the (5)-(8) range where the drainage ditch has become terribly overgrown), the distance is achievable if you can throw 200 feet, and the lines are clear and hittable without too much experience.
Cons:
We've got a few issues due to the park being jammed in too tight, and there just isn't that much super memorable here.
Let's start with the navigation and flow. Holes (1)-(9) are pretty straightforward. However, then we have to walk probably a quarter of a mile around two ball fields to get to (10). No navigational cues--you'll absolutely need a course map or UDisc. Then from (12)-(13) we have another transition over 1,000 feet that may have you wondering if you're on the right track. (15)-(16) is also a sketchy transition requiring a lengthy walk along the road. On the bright side, (18) ends near (1). HMP would benefit greatly from navigation cues.
Safety is a big issue at HMP. Roads and paths come into play on the first couple and last few holes, and even some in between.
There's also a very high risk of losing discs for a rec-level course. Fenced off areas such as retention ponds play right along the prime flight path on (3), (6), and especially the very tight putter shot on (9). The rough gets pretty scary in parts of (5)-(8) and could swallow a disc that went deep.
Lastly, HMP just lacks anything particularly memorable or special. There are a few nice park-style holes like (2), (4), the hillside basket (7), (8), and (16). However, the rec-level player should be a bit embarrassed to take bogey on any of these holes, as it would require two terrible throws (or a throw OB). As a course for new players, HMP scores 4.0 or higher. In the scheme of all disc golf courses' offerings in terms of fresh and interesting gameplay, not so great. This is especially pronounced in the (10)-(14) region of the course. These holes are all under 250' with no special challenge, and many feel like they've been crammed in beside roads and along ballfields.
Other Thoughts:
HMP is a nice rec-level course. Good variety (even that par 4!) makes it entertaining to play. Its pleasant situation in the park doesn't hurt either, and it would be a wonderful place to learn the game.
So why the 2.5? The safety issues, egregious flow from (9)-(13), lack of enduring challenge, and dull stretch of too-short holes on the back nine definitely detract. With the trend for newer courses seeming to me to be very high quality, I think HMP takes a very solid Decent/Typical. It's lacking the return appeal that my other 3.0 courses offer. Is it fun to golf here? Absolutely. A 2.5 for HMP shouldn't be taken as an insult, for a Typical disc golf course means everything is in place to have great fun.