Treasure Island Dizzy

The Good
Not much to say about the graphics - Spectrum just didn't offer the technical possibilities for good graphics. (The Amiga version is much better, but I haven't played this one.) Nowadays it can be played by people who own neither and old Spectrum machine nor a Spectrum emulator in two ways: with an online emulator (such a version is found on the Polish Dizzy site, dizzy.pl) or as a Dizzy AGE remake. The latter version has slightly improved graphics - the tree bark is brown and not red, no more merging of other colors with white surfaces (such as Dizzy himself or some items)... far from what Dizzy AGE graphics can look like (now games are being made which are still based on the Spectrum variant of Dizzy graphics, but with beautiful effects such as shading and transparency), but clearly better than the original.
Despite being difficult to play and plan, the game is quite fun when you learn how to pass some (intellectually) tighter points. It doesn't have much story - Dizzy is on an island and has to find a way to get back home - but anyway, even without graphics to appreciate and without a more inventive story, the island does seem intriguing.
An interesting detail are advertisements for other games. Some "scrolls" found throughout the game don't offer information or hints about the surroundings, but just let you know there is another interesting game. At first I found it rather annoying, but later, when "collecting" Easter eggs in Sierra games, I started to appreciate all kinds of inter-game references.

The Bad
For a relatively simple adventure-arcade game it requires much planning. It's mostly caused by two factors: only a single life available and the specific inventory system. In the most classic Dizzy adventures such as "Fantasy World Dizzy", "Magicland Dizzy" or "Prince of the Yolkfolk" the system is simple: you press a key to bring up the menu and choose and item - the inventory is much smaller than in "pure" adventure games, but as easy to use. In "Treasure Island Dizzy" the inventory is on the top of the screen and you always first drop the item on the top of the list. In "Fantastic Adventures of Dizzy" this kind of inventory system returned, but there taking off the scuba diving set under water didn't mean immediate death - Dizzy simply could spend just a little time holding his breath. In "Treasure Island Dizzy" there is no energy bar and just a single life, so you had to watch out to have the snorkel on the bottom of the item menu when going into the water. This makes playing the game more complicated - in a typical Dizzy adventure a la "Magicland" it's simple: the "give x to Y to get z" type of puzzle. In "Treasure Island Dizzy" item order is very important in some places.
As for the single life (maybe realistic, but quite a shock compared with lots of available lives in the first Dizzy adventure), I've read an explanation saying that traps in the tree village caused some complications and authors decided to avoid them by eliminating extra lives. To be honest, I don't "buy" this explanation... Anyway, just one life, no energy bar and an unforgiving inventory system combine to make "Treasure Island Dizzy" a kind of game where a single mistake means starting all over again.
Fortunately, when you get used to it and plan everything along with item order, the game isn't very difficult anymore - movement of dangerous animals and objects is foreseeable.

The Bottom Line
The game is quite hard due to lots of planning associated with item order, however when you get used to it, it can rather be perceived as an interesting challenge, a "strategic" element to the game. Anyway, it's just the beginning of the Dizzy series and the Oliver Twins (the creators of Dizzy) were still teenagers, so it seems they were using some trial and error to find a good balance between challenge and fun. Later they didn't repeat such a combination of obstacles as in this game, so I guess fans must have complained about them.